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Heat, Humidity and Humans



Homeostasis is an important biological function in humans. Homeostasis is when the body adjusts to external changes in the environment in order to maintain the internal conditions that are best for humans. However, even our internal regulation has its limits. For example, our body temperature is an important aspect that has to be kept constant to maintain the optimum temperature for chemical reactions in the body. But humans can only keep a stable temperature in certain combinations of heat and humidity before we start to experience heat-related health problems like heat stroke and heart attacks. 


Climate change is a phenomenon that has definitely affected the temperatures and the amountof heat humans must withstand. Since the start of the industrial revolution, the global temperature has gone up by around 1ºC. As the temperature continues to rise, people will begin to feel warmer. In response to this the body pumps more blood around the body that carries heat away from the skin. We also start to sweat, so that when water evaporates it carries heat with it and our skin is left feeling cooler. At certain levels, it becomes too hot or humid to maintain the ideal temperature and our body temperature starts to rise. While this isn’t an immediate threat, if we do not find a way to stay cool we can experience serious consequenes to our health such as heat exhaustion, heat stroke, and stress on the heart that may lead to heart attacks. 


In this research paper, scientists modelled the global temperature increase ranging between 1.5 ºC and 4 ºC to identify place son the planet where warming would lead to levels of heat and humidity that go beyond the limit at which humans can still survive. They found that if temperatures increase by 2ºC, 2.2 billion people in the Indus River Valley region of India and Pakistan, 1 billion people in Eastern China, and 800 million people in Sub-Saharan Africa will experience annual hours of heat that go beyond tolerable limits. Above 3ºC, this heat will start to effect the central and eastern seaboard of the USA and Australia. They also found that humid heat, such as high humidity heat waves, is a much bigger threat than dry heat. The more humid the air around us is, the more it is already saturated with water vapour and the less sweat can evaporate from our skin. This means that a majoy way that we maintain our body temperature is no longer effective. 


To combat these changes around the globe, scientists have recommended reducing greenhouse gas emissions, especially carbon dioxide emissions arising from the burning of fossil fuels. However, these models only predict the probability of certain trends that may take place in the future. They do not account for specific events that amy affect the climate and the individual tolerance of humans to levels of heat that may vary by many factors like their level of activity. 


By Nyrika


Works cited

Byjus. “Homeostasis.” BYJUS, Byju’s, 2018, byjus.com/biology/homeostasis/. Accessed 28 Oct. 2023.

MyTutor. “Why Is It Important to Regulate Body Temperature? What Is the Role of Our Skin in Regulating Our Body Temperature? | MyTutor.” Mytutor.co.uk, 2013, www.mytutor.co.uk/answers/6079/GCSE/Biology/Why-is-it-important-to-regulate-body-temperature-What-is-the-role-of-our-skin-in-regulating-our-body-temperature/. Accessed 28 Oct. 2023.

Science Daily. “Climate-Driven Extreme Heat May Make Parts of Earth Too Hot for Humans.” ScienceDaily, 9 Oct. 2023, www.sciencedaily.com/releases/2023/10/231009191623.htm. Accessed 28 Oct. 2023.


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